The pulling of the trigger of firearms of the revolver type to effect operation of the hammer for accurate firing of the weapon has presented a problem for many years. This is especially true when preliminary cocking of the hammer is not resorted to, as in the case of police work. The relative high pressure or force required to pull or squeeze the trigger results in the deflection of the weapon off to one side and impairs the accuracy of the shooting.
Many improved mechanisms for this purpose are found in the prior art. Those currently known to applicant are set forth below.
Stern, U.S. Pat. No. 845,274 utilizes a helical spring in tension against the hammer, the latter being pivoted to make this possible. This was practicable in an old style revolver, circa 1907, when this patent issued.
Lisle, U.S. Pat. No. 970,248 utilizes a helical spring especially adapted to operate the mechanism for improved utilization of the explosive charge.
Leggett, et al, U.S. Pat. No. 1,007,709 uses a helical spring in combination with a novel and rather complicated mechanism for improved action of the hammer relative to the barrel. This is in combination with a rather complicated trigger mechanism.
Johnson, U.S. Pat. No. 1,004,172 appears to be closest in appearance to applicant's invention, but is significantly different and does not perform the function which applicant does as set forth below.
Cobb, U.S. Pat. No. 1,046,268 is merely an improvement on the Johnson patent cited above.
Johansson, U.S. Pat. No. 1,586,810 is comprised of a helical spring which performs a routine function and the novely lies in the longitudinal rather than the pivotal action of the trigger.
Miller, U.S. Pat. No. 3,055,270. This likewise teaches a helical spring in connection with an automatic revolver having recoiling cylinder frame.
Rohm, U.S. Pat. No. 3,548,530. The spring action here is similar to the other patents cited where the hammer and trigger are pivotally mounted on one side of a cover plate.
Baker, U.S. Pat. No. 3,733,730 teaches a rather elaborate mechanism for providing a constant trigger pull at all positions of the barrel.
Hillberg, et al, U.S. Pat. No. 3,810,326 uses a novel construction of sub-assemblies of which the spring is a component part.
Baker, U.S. Pat. No. 3,996,686 teaches a construction in which the helical spring is part of a mechanism in which a gear segment is utilized for transmissions of the action of the trigger to the hammer.
All of the above prior art entails use of helical springs in various combinations. The helical springs are almost invariably used in combination with a concentric plunger sliding within the spring, the whole assembly being rigidly fixed at each end. No flexibility is provided. Their action is akin to that of a spring operated poppet valve. In every case the springs are fixed, at at least one end and sometimes at both ends.
It is known that the functioning of a helical spring is affected by the manner in which the ends are constrained, that is whether fixed or hinged. (See Kent's Mechanical Engineers' Handbook - 12th Edition pp. 11-14 to 11 - 15.)
The effect of lateral or transverse loading of helical springs is also understood although it is attended by rather complicated mathematical analysis so that emperical methods are usually employed to get the best spring action for a given application. (See A. M. Wahl, Mechanical Springs. Penton Publishing Company, Cleveland 1944.)
I am not aware of any attempts to basically improve the spring action of a revolver hammer before my improvement disclosed herein.
Some commercial revolvers utilize a leaf spring rather than a helical spring to provide the spring action necessary for operation of the hammer. A leaf spring does provide a certain amount of flexibility, overcomes some of the above disadvantages insofar as uniformity of force required to pull the trigger is concerned, but is disadvantageous in that it still requires a relatively hard pull on the trigger to operate the hammer, which pull is still far from uniform throughout its travel.